/* Generic sibling call optimization support
- Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000, 2001, 2002, 2003
+ Free Software Foundation, Inc.
This file is part of GCC.
#include "config.h"
#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
#include "rtl.h"
#include "regs.h"
return in the sibcall sequence. */
static rtx return_value_pseudo;
-static int identify_call_return_value PARAMS ((rtx, rtx *, rtx *));
-static rtx skip_copy_to_return_value PARAMS ((rtx));
-static rtx skip_use_of_return_value PARAMS ((rtx, enum rtx_code));
-static rtx skip_stack_adjustment PARAMS ((rtx));
-static rtx skip_pic_restore PARAMS ((rtx));
-static rtx skip_jump_insn PARAMS ((rtx));
-static int call_ends_block_p PARAMS ((rtx, rtx));
-static int uses_addressof PARAMS ((rtx));
-static int sequence_uses_addressof PARAMS ((rtx));
-static void purge_reg_equiv_notes PARAMS ((void));
-static void purge_mem_unchanging_flag PARAMS ((rtx));
-static rtx skip_unreturned_value PARAMS ((rtx));
+static int identify_call_return_value (rtx, rtx *, rtx *);
+static rtx skip_copy_to_return_value (rtx);
+static rtx skip_use_of_return_value (rtx, enum rtx_code);
+static rtx skip_stack_adjustment (rtx);
+static rtx skip_pic_restore (rtx);
+static rtx skip_jump_insn (rtx);
+static int call_ends_block_p (rtx, rtx);
+static int uses_addressof (rtx);
+static int sequence_uses_addressof (rtx);
+static void purge_reg_equiv_notes (void);
+static void purge_mem_unchanging_flag (rtx);
+static rtx skip_unreturned_value (rtx);
/* Examine a CALL_PLACEHOLDER pattern and determine where the call's
return value is located. P_HARD_RETURN receives the hard register
that the function used; P_SOFT_RETURN receives the pseudo register
- that the sequence used. Return non-zero if the values were located. */
+ that the sequence used. Return nonzero if the values were located. */
static int
-identify_call_return_value (cp, p_hard_return, p_soft_return)
- rtx cp;
- rtx *p_hard_return, *p_soft_return;
+identify_call_return_value (rtx cp, rtx *p_hard_return, rtx *p_soft_return)
{
rtx insn, set, hard, soft;
/* If we didn't get a single hard register (e.g. a parallel), give up. */
if (GET_CODE (hard) != REG)
return 0;
-
+
/* Stack adjustment done after call may appear here. */
insn = skip_stack_adjustment (insn);
if (! insn)
insn = NEXT_INSN (insn);
if (! insn)
return 0;
-
+
/* We're looking for a source of the hard return register. */
set = single_set (insn);
if (! set || SET_SRC (set) != hard)
copy. Otherwise return ORIG_INSN. */
static rtx
-skip_copy_to_return_value (orig_insn)
- rtx orig_insn;
+skip_copy_to_return_value (rtx orig_insn)
{
rtx insn, set = NULL_RTX;
rtx hardret, softret;
/* The destination must be the same as the called function's return
value to ensure that any return value is put in the same place by the
- current function and the function we're calling.
+ current function and the function we're calling.
Further, the source must be the same as the pseudo into which the
called function's return value was copied. Otherwise we're returning
value, return insn. Otherwise return ORIG_INSN. */
static rtx
-skip_use_of_return_value (orig_insn, code)
- rtx orig_insn;
- enum rtx_code code;
+skip_use_of_return_value (rtx orig_insn, enum rtx_code code)
{
rtx insn;
/* In case function does not return value, we get clobber of pseudo followed
by set to hard return value. */
static rtx
-skip_unreturned_value (orig_insn)
- rtx orig_insn;
+skip_unreturned_value (rtx orig_insn)
{
rtx insn = next_nonnote_insn (orig_insn);
Otherwise return ORIG_INSN. */
static rtx
-skip_stack_adjustment (orig_insn)
- rtx orig_insn;
+skip_stack_adjustment (rtx orig_insn)
{
rtx insn, set = NULL_RTX;
return it. Otherwise return ORIG_INSN. */
static rtx
-skip_pic_restore (orig_insn)
- rtx orig_insn;
+skip_pic_restore (rtx orig_insn)
{
rtx insn, set = NULL_RTX;
Otherwise return ORIG_INSN. */
static rtx
-skip_jump_insn (orig_insn)
- rtx orig_insn;
+skip_jump_insn (rtx orig_insn)
{
rtx insn;
goes all the way to END, the end of a basic block. Return 1 if so. */
static int
-call_ends_block_p (insn, end)
- rtx insn;
- rtx end;
+call_ends_block_p (rtx insn, rtx end)
{
rtx new_insn;
/* END might be a note, so get the last nonnote insn of the block. */
is found outside of some MEM expression, else return zero. */
static int
-uses_addressof (x)
- rtx x;
+uses_addressof (rtx x)
{
RTX_CODE code;
int i, j;
of insns. */
static int
-sequence_uses_addressof (seq)
- rtx seq;
+sequence_uses_addressof (rtx seq)
{
rtx insn;
/* Remove all REG_EQUIV notes found in the insn chain. */
static void
-purge_reg_equiv_notes ()
+purge_reg_equiv_notes (void)
{
rtx insn;
/* Clear RTX_UNCHANGING_P flag of incoming argument MEMs. */
static void
-purge_mem_unchanging_flag (x)
- rtx x;
+purge_mem_unchanging_flag (rtx x)
{
RTX_CODE code;
int i, j;
the CALL_PLACEHOLDER insn; USE tells which child to use. */
void
-replace_call_placeholder (insn, use)
- rtx insn;
- sibcall_use_t use;
+replace_call_placeholder (rtx insn, sibcall_use_t use)
{
if (use == sibcall_use_tail_recursion)
- emit_insns_before (XEXP (PATTERN (insn), 2), insn);
+ emit_insn_before (XEXP (PATTERN (insn), 2), insn);
else if (use == sibcall_use_sibcall)
- emit_insns_before (XEXP (PATTERN (insn), 1), insn);
+ emit_insn_before (XEXP (PATTERN (insn), 1), insn);
else if (use == sibcall_use_normal)
- emit_insns_before (XEXP (PATTERN (insn), 0), insn);
+ emit_insn_before (XEXP (PATTERN (insn), 0), insn);
else
abort ();
pass above from deleting it as unused. */
if (XEXP (PATTERN (insn), 3))
LABEL_PRESERVE_P (XEXP (PATTERN (insn), 3)) = 0;
-
+
/* "Delete" the placeholder insn. */
remove_insn (insn);
}
Replace the CALL_PLACEHOLDER with an appropriate insn chain. */
void
-optimize_sibling_and_tail_recursive_calls ()
+optimize_sibling_and_tail_recursive_calls (void)
{
rtx insn, insns;
basic_block alternate_exit = EXIT_BLOCK_PTR;
bool no_sibcalls_this_function = false;
- int successful_sibling_call = 0;
- int replaced_call_placeholder = 0;
+ bool successful_replacement = false;
+ bool replaced_call_placeholder = false;
edge e;
insns = get_insns ();
- /* We do not perform these calls when flag_exceptions is true, so this
- is probably a NOP at the current time. However, we may want to support
- sibling and tail recursion optimizations in the future, so let's plan
- ahead and find all the EH labels. */
- find_exception_handler_labels ();
-
- rebuild_jump_labels (insns);
- /* We need cfg information to determine which blocks are succeeded
- only by the epilogue. */
- find_basic_blocks (insns, max_reg_num (), 0);
cleanup_cfg (CLEANUP_PRE_SIBCALL | CLEANUP_PRE_LOOP);
/* If there are no basic blocks, then there is nothing to do. */
if (n_basic_blocks == 0)
return;
- /* If we are using sjlj exceptions, we may need to add a call to
+ /* If we are using sjlj exceptions, we may need to add a call to
_Unwind_SjLj_Unregister at exit of the function. Which means
that we cannot do any sibcall transformations. */
if (USING_SJLJ_EXCEPTIONS && current_function_has_exception_handlers ())
/* Walk forwards through the last normal block and see if it
does nothing except fall into the exit block. */
- for (insn = BLOCK_HEAD (n_basic_blocks - 1);
+ for (insn = EXIT_BLOCK_PTR->prev_bb->head;
insn;
insn = NEXT_INSN (insn))
{
sibling call optimizations, but not tail recursion.
Similarly if we use varargs or stdarg since they implicitly
may take the address of an argument. */
- if (current_function_calls_alloca
- || current_function_varargs || current_function_stdarg)
+ if (current_function_calls_alloca || current_function_stdarg)
sibcall = 0;
/* See if there are any reasons we can't perform either sibling or
|| current_function_calls_setjmp
/* Can't if more than one successor or single successor is not
exit block. These two tests prevent tail call optimization
- in the presense of active exception handlers. */
+ in the presence of active exception handlers. */
|| call_block->succ == NULL
|| call_block->succ->succ_next != NULL
|| (call_block->succ->dest != EXIT_BLOCK_PTR
/* Select a set of insns to implement the call and emit them.
Tail recursion is the most efficient, so select it over
a tail/sibling call. */
- if (sibcall)
- successful_sibling_call = 1;
- replaced_call_placeholder = 1;
- replace_call_placeholder (insn,
- tailrecursion != 0
+ if (sibcall || tailrecursion)
+ successful_replacement = true;
+ replaced_call_placeholder = true;
+
+ replace_call_placeholder (insn,
+ tailrecursion != 0
? sibcall_use_tail_recursion
: sibcall != 0
? sibcall_use_sibcall
}
}
- if (successful_sibling_call)
+ if (successful_replacement)
{
rtx insn;
tree arg;
/* A sibling call sequence invalidates any REG_EQUIV notes made for
- this function's incoming arguments.
+ this function's incoming arguments.
At the start of RTL generation we know the only REG_EQUIV notes
in the rtl chain are those for incoming arguments, so we can safely
- flush any REG_EQUIV note.
+ flush any REG_EQUIV note.
This is (slight) overkill. We could keep track of the highest
argument we clobber and be more selective in removing notes, but it
/* A sibling call sequence also may invalidate RTX_UNCHANGING_P
flag of some incoming arguments MEM RTLs, because it can write into
those slots. We clear all those bits now.
-
+
This is (slight) overkill, we could keep track of which arguments
we actually write into. */
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
}
/* Similarly, invalidate RTX_UNCHANGING_P for any incoming
- arguments passed in registers. */
- for (arg = DECL_ARGUMENTS (current_function_decl);
- arg;
+ arguments passed in registers. */
+ for (arg = DECL_ARGUMENTS (current_function_decl);
+ arg;
arg = TREE_CHAIN (arg))
{
if (REG_P (DECL_RTL (arg)))
}
}
- /* There may have been NOTE_INSN_BLOCK_{BEGIN,END} notes in the
+ /* There may have been NOTE_INSN_BLOCK_{BEGIN,END} notes in the
CALL_PLACEHOLDER alternatives that we didn't emit. Rebuild the
lexical block tree to correspond to the notes that still exist. */
if (replaced_call_placeholder)
/* This information will be invalid after inline expansion. Kill it now. */
free_basic_block_vars (0);
+ free_EXPR_LIST_list (&tail_recursion_label_list);
}